Philip Pullman's His Dark Materials is a solid choice. It gets dark, but so does Harry Potter, so fair game. I would say late grade school for the first book, adolescent for books 2 and 3.
Tamora Pierce has written a number of kid appropriate fantasy books with solid writing and strong female characters. I have seen countless grade school girls get hooked on her work. Some of her books just start to get into more mature relationship themes, but it's enough to embarrass your kid a bit, not scar them.
As a child I enjoyed C.S. Lewis, but was personally affronted when I got to the last Narnia book and discovered that good story had been compromised for christian allegory. Lewis won't make your child a bible thumped any more than Pullman will make them an atheist. Just make sure you know what your kid is reading, and find opportunities to discus the material with them critically!
Ursula K. Le Guin's Earthsea series is another excellent option. I believe when I read it in grade school I found the pacing too slow, so I skipped ahead a lot and inferred a number of plot points. Nonetheless, I'm certain I enjoyed it the first time, it influenced my view of fantasy literature, and I have returned to reread the series multiple times since.
The Hobbit is a great kids book.
Alison Croggon's Pellinor series is less well known, but perfect for pre/early teens that love fantasy.
The Enchanted Forest Chronicles by Patricia Wrede feature a princess who runs away from home to work for a dragon. Solid writing, strong female characters, Pratchett-esque subversion of fantasy tropes. Fun and appropriate for grade school kids.
Howl's Moving Castle by Diana Wynne Jones
That's off the top of my head. Of these books I consider Pullman, Le Guin, and Tolkien to be literature (worth an adult's time), while the others are just fun and well written.
It's not about edge. My children are free to make up their own minds about what they do with their lives when they reach an age where they can reason for themselves. Until then, I do my best to keep any ideological or religious influence from trying to exert itself upon them.
I don't think 'Be nice to others' is ideology. It may be part of an ideology, but I don't think that it an ideology in itself.
'Be nice to others' is also not a totalizing idea in the same way that Christianity is - not everything in the world happens because somebody was or was not nice to others. Christianity takes as its base that everything is/was the will of their god.
Narnia is only an "ideological or religious influence" if you're already very familiar with Christian symbolism. 99% of children will never get the references.
